Module pool 

Managed resource pools — capacity gate, idle reuse, optional TTL, invalidation.

Built from crate::coordination::semaphore::Semaphore, crate::coordination::synchronized_ref::SynchronizedRef, and crate::resource::scope::Scope finalizers (check-in on scope close). Waiting for capacity is the semaphore acquire; an idle slot becomes available when a prior checkout’s scope ends.

Structs

KeyedPool

Pool partitioned by key; total concurrent checkouts across all keys is bounded by capacity.

Pool

Fixed-capacity pool with reuse of returned values and optional TTL on idle slots.